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CASE STUDY: MIRAGE IN DESERTS
To a distant observer, the light appears to be coming from somewhere below the ground. The observer naturally assumes that light is being reflected from the ground, say, by a pool of water near the tall object. Such inverted images of distant tall objects cause an optical illusion to the observer. This phenomenon is called mirage. This type of mirage is especially common in hot deserts. Based on the above facts, answer the following questions:
(a) Which of the following phenomena is prominently involved in the formation of mirage in deserts?
(i) Refraction, Total internal Reflection
(ii) Dispersion and Refraction
(iii) Dispersion and scattering of light
(iv) Total internal Reflection and diffraction.
Answer
- In places like deserts, the ground is very cold, and the surrounding air relatively cold.
- This leads to the layer closest to the ground to heat up.
- Refracted light undergoes Total internal reflection between the layers of air leading to the formation of a mirage.
So the correct answer is (i)
